Oncologically Safe Distal Resection Margins in Rectal Cancer Patients Treated with Chemoradiotherapy

Introduction Although current guidelines recommend distal resection margins (DRM) of 2–5 cm in rectal cancer operation, smaller margins may be safe. We therefore assessed the impact of distal margins on outcomes in patients with rectal cancer treated with neoadjuvant chemoradiotherapy (CRT) followed by radical resection or resection followed by adjuvant CRT. Materials and methods This study involved 376 patients who underwent sphincter-saving resection for rectal adenocarcinoma and pre- or postoperative CRT between 2000 and 2006. DRMs were measured on pinned fixed specimens. We excluded patients who did not complete planned CRT and those with stage IV disease. A retrospective cross-sectional analysis was performed. Results No significant differences in local recurrence (9.8 versus 7.3 %; P = 0.324) and systemic recurrence (16.4 versus 18.7 %; P = 0.731) were observed in patients with DRMs of ≤5 and >5 mm, respectively. Moreover, in each DRM category, there were no differences in local and systemic recurrence rates between patients who received pre- or postoperative CRT. DRM did not affect overall survival ( P = 0.880) or 5-year survival rate (80.3 versus76.8 %; P = 0.340). Conclusion A distal margin of at least 5 mm with negative resection margin on frozen section does not reduce oncological safety in rectal cancer patients who receive pre- or postoperative CRT.